Altair 8800 Clone User manual

ALTAIR 8800 CLONE COMPUTER
OPERATOR’S MANUAL
Version 1.8, September 014
TABLE OF CONTENTS
INTRODUCTION ............................................................... 1
PART 1 – ALTAIR 8800 CLONE HARDWARE SPECIFICATIONS .........................
PART – CONFIGURATION MONITOR ............................................. 4
A. Floppy Disk Menu ....................................................... 4
B. PROM Menu .............................................................. 6
C. Serial Port Menu ....................................................... 7
D. Load .BIN or .HEX File ................................................. 9
E. Administration Menu .................................................... 9
PART 3 – TERMINAL EMULATOR ................................................ 13
A. Overview .............................................................. 13
B. TeraTerm Terminal Emulator ............................................ 13
C. Installing TeraTerm ................................................... 13
D. Configuring TeraTerm .................................................. 13
E. Using TeraTerm ........................................................ 14
PART 4 – ALTAIR 8800 DEMONSTRATIONS ....................................... 15
A. Kill-the-Bit Front Panel Game ......................................... 15
B. Loading and Using 4K BASIC from Paper Tape ............................ 17
C. Loading and Using 8K BASIC from Cassette .............................. 0
D. Loading and Using Disk BASIC from Floppy Disk......................... 4
E. Loading and Using Altair DOS .......................................... 6
F. Loading and Using CP/M ................................................ 9
G. Loading and Using Timesharing BASIC ................................... 31

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INTRODUCTION
The original Altair 8800 is the best computing platform available for reliv-
ing the birth of the personal computing revolution. You will find your new
Altair Clone to be the next best thing!
For most users, the Altair computing environment of today is, out of neces-
sity, slightly different than the computing environment of the mid 1970s.
However, once familiar with these differences, you can follow right along
with Altair owners of the 1970s – even using original Altair documentation
and software - to experience first-hand the thrill of using these early per-
sonal computers.
NEXT STEPS
The best way to proceed from here is up to you!
If you want as real an “Altair Experience” as possible, first, understand the
hardware configuration of your Altair 8800 (Part 1, “Altair 8800 Clone Hard-
ware Specifications”), second, learn how to modify that configuration if
needed (Part , “Configuration Monitor”), then proceed from there using orig-
inal Altair documentation and software.
Original documents and supporting software are under the Support link on the
AltairClone.com website. It is recommended that you download the full Clone
support package by clicking on the All Manuals and Software as a .zip file
link, then extracting all files to your disk. Start your research by looking
at the “Altair 8800 Operator’s Manual.” Keep in mind that all the manuals
contain a mistake or two (or more!) and may send you down the wrong path at
times – that’s part of the fun!
If you want some help along the way, the Altair Experience link on the Al-
tairClone.com website provides a great list of topics and tutorials you may
want to work through on your Altair Clone.
If you want to quickly set up a few popular Altair demonstrations, Part 4,
“Altair 8800 Demonstrations” gives step-by-step instructions for the follow-
ing activities:
• Kill-the-Bit front panel game
• Loading and using 4K BASIC from paper tape
• Loading and using 8K BASIC from cassette
• Loading and using Disk BASIC from floppy disk
• Loading and using Altair DOS
• Loading and using CP/M
• Loading and using Timesharing BASIC

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PART 1 – ALTAIR 8800 CLONE HARDWARE SPECIFICATIONS
A. RAM
64K of RAM with memory protect in 56 byte pages. If any PROMs are loaded and
enabled, the overlaid RAM is replaced by PROM in 56 byte increments.
B. PROM
Eight “sockets” of up to K each provide for up to 16K of PROM. Loaded and
enabled PROMs overlay and replace RAM in 56 byte increments. A feature pre-
sent in the 8800b Turn-Key computer to disable PROM (in order to re-enable
RAM) can be turned on if desired. See “Administration Menu” in Part , “Con-
figuration Monitor” for more information.
C. Serial Ports
Two serial ports are wired to DB- 5 connectors on the rear of the computer.
The port types can be configured to match original Altair hardware as shown
below. The optional Audio Cassette Interface adds the third serial port. The
first row illustrates the default configuration.
Serial Port 1
(Top Connector)
Serial Port
(Bottom Connector)
Serial Port 3
(from Cassette Intf)
First port from 88- SIO
board at I/O address oc-
tal 0/ 1
88-SIO port at I/O ad-
dress 6/7 (the Altair
cassette serial port)
First port from a second
88- SIO board at I/O ad-
dress octal 4/ 5
88-SIO port at I/O ad-
dress 0/1
Second port from 88- SIO
board at I/O address oc-
tal / 3
88-SIO port at I/O ad-
dress 6/7 (the Altair
cassette serial port)
The serial ports are wired as follows:
Pin Signal
3
4
5
7
XMT from Terminal (out) to Clone (in)
RCV to Terminal (in) from Clone (out)
RTS from Terminal (out) to Clone (CTS in)
CTS to Terminal (in) from Clone (RTS out)
Signal Ground
By default, pin 4 RTS (which becomes CTS inside the Clone) is always asserted
inside the Clone and therefore does not need to be connected on the DB- 5 if
active handshaking is not used. RTS is not present or used on Port 3.
By default, pin 5 CTS (which is driven from RTS inside the Clone) is always
asserted in case an asserted handshake signal is required by the peripheral
device. CTS is not present or used on Port 3.
The ACIA on the 88- SIO board supports programmed hardware handshaking. If
your applications requires this feature, the ACIA’s handshake lines can be
configured to be fully active. See “Set CTS, RTS Usage” in the “Serial Port
Menu” section of Part , “Configuration Monitor” for more information.
D. Line Printer Port
The Altair Clone implements the Altair 88-LPC line printer interface board.
This board is supported by Altair BASIC, Altair DOS, CP/M 1.4 and CP/M . .
When prompted for the printer type in Altair BASIC or Altair DOS, choose “O”
(capital letter “oh”) to select the 88-LPC interface.

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In the Altair Clone, data sent to the 88-LPC is transmitted out serial port
, which in turn, can be connected to a terminal emulator window to view
printer output, or connected directly to a serial printer. Normal serial port
functions of port still work when routing 88-LPC output through the port.
For example, serial port can be used as the cassette interface to load and
save programs and to also see line printer output.
If needed, the 88-LPC can be disabled if it interferes with your use of se-
rial port . See “Line Printer controller” in the “Administration Menu” sec-
tion of Part , “Configuration Monitor” for more information.
E. Floppy Drives
The Altair Clone provides three floppy “drives” that duplicate the function-
ality of the original Altair 8 inch floppy drives or the Altair Minidisk 5. 5
inch drive. Floppy storage is implemented using non-volatile RAM inside the
Altair Clone. Since physical floppy disks and drives are not present, “in-
serting” a floppy disk is done by uploading a floppy image from a PC to the
Clone. Conversely, a floppy image on the Clone can be saved back to a PC for
archiving.
Once uploaded to the Clone, floppy disk content is non-volatile and further
data exchange with a PC is not required to use the floppy drives. Floppy
disks can be swapped between the three drives (to put a different disk into
drive zero to boot, for example) without having to connect to a PC. The “Con-
figuration Monitor” makes floppy disk handling simple. See “Floppy Disk Menu”
in Part , “Configuration Monitor” for more information.
F. Interrupts and the 88-VI/RTC Board
Interrupts in the Altair 8800 Clone can be generated by the serial ports
( SIO and/or SIO for both transmit and receive), the floppy disk controller
("sector true" interrupt at the start of each sector), and by the real-time
clock present on the 88-VI/RTC board.
The 88-VI/RTC Vectored Interrupt/Real-Time Clock board prioritizes interrupts
to the 8080 processor from the vectored interrupt lines (VI0-VI7) on the Al-
tair bus. The board can also provide 60hz real-time clock interrupts. While
not widely used for most commercial software, the VI/RTC board is required by
MITS Time-Sharing BASIC for the Altair.
If the 88-VI/RTC board is not enabled, then the default interrupt structure
of the Altair (PINT with RST7) is used. In this case, all devices can be tied
into the PINT line at the same time as the emulated devices all drive the
PINT line with open collector outputs. As with the original hardware, all
boards (other than the 88-VI/RTC) ignore the 8080 interrupt acknowledge cy-
cle, so the 8080 processor sees a RST7 instruction on the bus (all data bits
high) during the interrupt acknowledge cycle.
Connection of device interrupt outputs to the desired vectored interrupt line
on the Altair bus (VI0-VI07) is done in the “Interrupt Vector Assignments”
menu of the “Administration Menu.” See these menus in Part , “Configuration
Monitor” for more information.
G. Changing Hardware Configuration
If an original Altair owner needed to install a new serial I/O card, install
or remove a PROM, or change a baud rate jumper, the owner opened the computer
and made the required modifications inside the computer. In the Altair 8800
Clone, these hardware configuration changes are made using menu options in
the “Configuration Monitor.” See Part , “Configuration Monitor” for more in-
formation.

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PART – CONFIGURATION MONITOR
The Configuration Monitor is used to manage the physical and virtual hardware
in the Altair 8800 Clone. The monitor is a simple menu driven program built
into the Clone. Communication with the operator is always via serial port 1
at 9600 baud, 8N1.
To enter the Configuration Monitor, raise and hold the STOP/RUN switch in the
STOP position, then raise the left AUX switch. The main menu is displayed:
===== System Configuration Monitor 1.7 =====
1) Floppy Disk Menu
) PROM Menu
3) Serial Port Menu
4) Load .BIN File
5) Load .HEX File
6) Admin Menu
x) Exit to Altair
IMPORTANT: Exiting the Configuration Monitor and returning to normal Altair
operation should always be performed by backing out of sub-menus to the main
menu shown above, then choosing the “Exit to Altair” menu option.
A. Floppy Disk Menu
The floppy disk menu is used to insert, remove and manage floppy disks. Flop-
py disks are byte for byte images of actual Altair floppy disks and are ini-
tially uploaded to the Clone from a PC. Floppy disk content is stored in non-
volatile RAM inside the Clone and once uploaded, is always available.
When the floppy disk option is selected from the main menu, the content of
each drive is shown. The drive numbers listed are the same drive numbers used
with real Altair drives.
===== Floppy Drive Content =====
(8 inch floppy drives)
Drive 0 – CP/M .
Drive 1 – Disk BASIC Games
Drive – Altair DOS
Choose Drive Number to Update (x to exit):
When a drive number is selected, the following menu is displayed:
===== Floppy Drive Menu =====
1) Change Drive Assignment
) Insert Floppy (Load Content from PC)
3) Save Floppy Content to PC
4) Change Floppy Description
x) Exit this Menu
1. Change Drive Assignment
The “Change Drive Assignment” option is used to change which drive a floppy
disk is in. This is typically used to put a different disk into drive zero
for booting. The selected disk is swapped with the disk presently in the des-
tination drive number.

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. Insert Floppy
The “Insert Floppy” option is used to load new content into a drive. The
floppy disk image is uploaded from a PC using the XMODEM protocol (original
XMODEM with 1 8 byte blocks and checksum). Compatible disk images files typi-
cally have a “.dsk” extension and are 330K or 75K in size (8 inch, minidisk).
The floppy image transfer is done at a higher baud rate to reduce the trans-
fer time. The default transfer rate is 115, 00 baud. This rate can be changed
in the “Baud Rate for Floppy Load/Save” option in the “Admin” menu.
Upon selecting the “Insert Floppy” option, the monitor confirms the operation
and prompts for a description of the new disk. The PC baud rate should then
be set to 115, 00 baud after which the XMODEM send operation can be initiated
on the PC. If using TeraTerm, a convenient shortcut is pressing CTRL-1 to set
the baud rate to 115, 00 baud. The new baud rate can be seen in the TeraTerm
title bar.
When the transfer completes, the user is prompted to return the PC baud rate
to 9600 baud. If using TeraTerm, a convenient shortcut is pressing CTRL-9 to
return the baud rate to 9600 baud. The new baud rate can be seen in the Ter-
aTerm title bar. This sequence is shown below:
===== Insert Floppy (Load Content) =====
This will over-write "Altair DOS." Are you sure (y/n)? y
Enter floppy description: New Disk
Step 1: Set terminal computer baud rate to 115. K
Step : Start XMODEM file SEND after setting the new baud rate...
(XMODEM transfer occurs here...)
Return terminal computer to 9600 baud, then press return:
If the XMODEM transfer must be aborted, first stop the transfer from the PC
end, then abort the Clone’s reception by raising and releasing the left AUX
switch.
3. Save Floppy Content to PC
This menu option is used to write a floppy disk image back to a PC for ar-
chiving. The floppy disk image is downloaded to the PC using the XMODEM pro-
tocol (original XMODEM with 1 8 byte blocks and checksum). The floppy image
transfer is done at a higher baud rate to reduce the transfer time. The de-
fault transfer rate is 115, 00 baud. This rate can be changed in the “Baud
Rate for Floppy Load/Save” option the “Admin” menu.
Upon selecting the “Save Floppy” option, the monitor confirms the operation
and prompts for the baud rate change. The PC baud rate should be set to
115, 00 baud after which the XMODEM receive operation can be initiated on the
PC. If using TeraTerm, a convenient shortcut is pressing CTRL-1 to set the
baud rate to 115, 00 baud. The new baud rate can be seen in the TeraTerm ti-
tle bar.
When the transfer completes, the user is prompted to return the PC baud rate
to 9600 baud. If using TeraTerm, a convenient shortcut is pressing CTRL-9 to
return the baud rate to 9600 baud. The new baud rate can be seen in the Ter-
aTerm title bar. This sequence is shown below:

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Save content of "Altair DOS" to the PC. Are you sure (y/n)? y
Step 1: Set terminal computer baud rate to 115. K
Step : Start XMODEM file RECEIVE after setting the new baud rate...
(XMODEM transfer occurs here...)
Return terminal computer to 9600 baud, then press return:
If the XMODEM transfer must be aborted, first abort the Clone transmission by
raising and releasing the left AUX switch, then stop the receive operation on
the PC end.
4. Change Floppy Description
Use this menu option to change the description of a drive’s content. This can
also be used to “eject” a floppy you’re no longer using by changing the de-
scription to “Scratch Disk” (or any similar description) to indicate the
drive is free to use. From the Altair’s perspective, a floppy disk is still
present in the drive, just consider it a blank or scratch disk.
-------------------------------------------
B. PROM Menu
The PROM menu is used to insert and remove PROMs. Eight slots are provided
for PROM content. Each slot is up to K bytes in length. PROM content is up-
loaded from a PC in binary (.bin) or Intel Hex (.hex) format. Once uploaded,
PROM content is non-volatile. PROM content can also be disabled without actu-
ally removing the PROM so that it can later be re-enabled without having to
re-upload the content from a PC.
When the PROM Menu option is chosen from the main menu, the current content
of each PROM slot is displayed as shown below:
===== PROM Information Table =====
Num Status Addr Length Description
--- --- ---- ------ -------------------
1 ON FF00 0100 Disk Boot Loader
ON FE00 0100 Multi-Boot Loader
3 ON FD00 0100 Turn-Key Monitor
4 OFF 0000 0000
5 OFF 0000 0000
6 OFF 0000 0000
7 OFF 0000 0000
8 OFF 0000 0000
Enter PROM Number to Update (x to exit):
To load or change the content of a PROM slot, enter the slot number. The fol-
lowing menu is displayed:
===== PROM Menu =====
1) Load New PROM Content
) Change Description
3) Change Load Address
4) Enable the PROM
5) Disable the PROM
6) Remove the PROM
x) Exit this Menu

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1. Load New PROM Content
The “Load New PROM Content” option is used to load new content into a PROM
slot. The PROM data can be uploaded as a binary or Intel hex format file. If
a binary format is chosen, the load address must be specified (up to four hex
digits). The example below shows loading PROM content from an Intel hex file.
File transfer can be aborted by pressing CTRL-C or raising the left AUX
switch.
===== Load New Prom Content =====
Enter PROM Address in hex (or return for .HEX file):
Send .hex file now...
(initiate simple send file operation from the PC – not XMODEM)
. Change Description, Change Load Address, etc.
Options – 6 are fairly self explanatory. Note: The “Change Load Address”
option does NOT magically relocate already assembled code. This option is
used if you accidentally typed in the wrong address when initially loading a
binary PROM file.
-------------------------------------------
C. Serial Port Menu
The serial ports on the Altair Clone can be configured in a variety of ways
to match the requirements of the software to be run. By default, port 1 is a
SIO port (Motorola ACIA) at octal address 0 0/0 1. Serial port defaults to
an SIO port at address 006/007 (the cassette interface port). If you pur-
chased an assembled Clone, serial port 1 is the upper DB- 5 on the rear panel
and serial port is the lower connector. If using the optional Audio Cas-
sette Interface, you’ll probably want to configure Port 3 to be the cassette
I/O port (SIO at 006/007, 300 baud, 8N1) instead of Port .
When the Serial Port Menu option is chosen from the main menu, the current
serial port settings are displayed as shown below (Note: The port settings
shown are also the default settings).
===== Serial Port Settings =====
Port Type I/O Rate Other
---- ---- ------- ---- --------
1 SIO 0 0,0 1 9600
SIO 006,007 9600 8N1
3 SIO 0 4,0 5 9600
Enter Serial Port to Change (x to Exit):
After entering the serial port number to change, this menu is displayed:
===== Serial Port Menu =====
1) Change Port Type
) Set Baud Rate
3) Set CTS, RTS Usage
4) Set Word Length, Parity, Stop Bits
x) Exit this Menu

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1. Change Port Type
The “Change Port Type” option is used to specify the type of Altair serial
port assigned to a physical serial port on the Altair Clone. The following
options are displayed:
===== Set Serial Port Type =====
1) SIO (Original serial board, Rev 1)
) SIO (Motorola 6850 ACIA)
x) Exit this Menu
The SIO port type duplicates operation of the original 88-SIO boards with the
status word modification in place. These are the most common versions of the
SIO board and are referred to as “not Rev 0” or “Rev 1” in Altair manuals.
Serial port 1 is at address 0/1 and serial ports and 3 are at address 6/7
(matches the SIO port used with the Altair cassette interface).
The SIO option duplicates operation of the 88- SIO boards which use the Mo-
torola ACIA as the UART. Serial port 1 is at octal address 0 0/0 1, port is
at octal address 0 /0 3, and port 3 is at octal address 0 4/0 5.
. Set Baud Rate
Self explanatory.
3. Set CTS, RTS Usage
This option only affects a serial port configured as a SIO port. The ACIA on
the SIO board allows use of handshake lines CTS and RTS. On a real 88- SIO
board, if the user did not want these signals to affect operation, they could
be tied active or inactive as needed. This menu option allows configuration
of how CTS and RTS are used.
If CTS is set to “Not Used,” CTS is permanently asserted “true” going into
the ACIA. If RTS is set to “Not Used,” RTS is permanently asserted “true” go-
ing out of the DB- 5 serial port connector. When either signal is set to
“Used,” the signal passes from/to the serial port to the ACIA as expected.
===== Set CTS, RTS Usage (Affects SIO Ports Only) =====
1) CTS, RTS Not Used
) Only RTS Used
3) Only CTS Used
4) CTS, RTS Both Used
x) Exit this Menu
4. Set Word Length, Parity, Stop Bits
This option only affects a serial port configured as an SIO port. To config-
ure word length, parity and stop bits on a real 88-SIO board, jumper wires
were used. This menu option allows configuration of these same jumper set-
tings. When this menu option is selected, the following menu is displayed:

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Set Word Length, Parity, Stop Bits (Affects SIO Ports Only)
1) 7E
) 7O
3) 7E1
4) 7O1
5) 8N
6) 8N1
7) 8E1
8) 8O1
x) Exit this Menu
D. Load .BIN or .HEX File
These options provide a convenient “cheat” to directly load a program or data
into Altair memory. Files are sent using simple 8-bit transfer (not XMODEM).
If a binary file is sent, the load address (up to four hex digits) must be
specified.
The example below shows loading memory from a binary file. File transfer can
be aborted by pressing CTRL-C or raising the left AUX switch.
Enter load address in hex: 0
Send .bin file now...
(initiate simple send file operation from the PC – not XMODEM)
-------------------------------------------
E. Administration Menu
When “Admin Menu” is selected from the main menu, the administration menu is
displayed:
===== Administration Menu =====
1) Interrupt Vector Assignments
) Line Printer Controller
3) Turnkey Module
4) Floppy Drive Type
5) Floppy Performance
6) Baud Rate for Floppy Load/Save
7) Single-Step "Down" Options
8) Restore Defaults
9) Update Firmware
x) Exit this Menu
1. Interrupt Vector Assignments
The 88-VI/RTC Vectored Interrupt/Real-Time Clock board in the Altair Clone is
used to prioritize interrupts to the 8080 processor from the vectored inter-
rupt lines on the Altair bus (VI0-VI7). In a real Altair, a device’s inter-
rupt output is connected to the desired vector line using a jumper. This menu
allows specification of that connection.
When this menu option is selected, the present vector assignments for inter-
rupt sources in the Clone are displayed:

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===== 88-VI/RTC Vectored Interrupt Assignments =====
Device Vector
------------- ---
1) Floppy Drives 0
) Serial Port 1
3) Serial Port
3) Serial Port 3 3
4) Real-Time Clk 1
Enter Device Number to Update (x to exit):
After specifying the device number to update, the user can choose a new in-
terrupt vector number (0-7) for the device. VI0 is the highest interrupt pri-
ority, VI7 is the lowest priority. For the Real-Time Clock only, a “D” for
“Disabled” can be entered as a vector number. This disables interrupts from
the RTC even if 8080 software enables them.
. Line Printer Controller
Altair BASIC, Altair DOS, CP/M 1.4 and CP/M . all support the Altair 88-LPC
line printer interface. When prompted for the printer type in Altair BASIC or
Altair DOS, choose “O” (capital letter “oh”) to select the 88-LPC interface.
In the Altair Clone, data sent to the 88-LPC can be routed to serial port ,
which in turn, can be connected to a terminal emulator window to view printer
output, or connected directly to a serial printer. This menu option allows
the user to enable or disable this feature. The default setting is for the
88-LPC output to be enabled.
Note that normal serial port functions of port still work when routing 88-
LPC output through the port. For example, serial port can be used as the
cassette interface to load and save programs and to also see line printer
output.
===== Line Printer Controller =====
Current setting: Line Printer Enabled on Serial Port
1) Enable Line Printer on Serial Port
) Disable Line Printer Output
x) Exit this Menu
3. Turnkey Module
The Altair Turnkey board can be installed or removed with this menu. The
Turnkey Module provides auto-start to a specified address (typically in ROM)
on power up or following a front panel reset.
The Turnkey Module also allows the 1K of ROM at 0xFc00 to 0xFFFF to overlay
RAM. ROM is enabled at power up and on reset. The ROM is disabled and RAM en-
abled upon execution of an IN instruction from 0xFE or 0xFF. Since 0xFF is
the sense switch port, booting from disk automatically enables all 64K of RAM
because the boot loader PROM (while executing from RAM) does an IN operation
from the sense switch port. Note that the Altair Multi-Boot Loader PROM (MBL)
fails to run properly with the Turnkey Module installed since this PROM reads
the sense switch port while executing from PROM, effectively killing itself.
===== Turnkey Module =====
Current setting: Disabled
1) Enable Turnkey Module
) Autostart Address: FF00
x) Exit this Menu

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4. Floppy Drive Type
This option is used to select between the Altair 8 inch floppy or the Altair
Minidisk. All three drives are affected. After switching drive type, be sure
to upload disk images appropriate for the drive type selected.
===== Floppy Drive Type =====
Current setting: 8 Inch Floppy
1) 8 Inch Floppy
) Minidisk Floppy
x) Exit this Menu
5. Floppy Performance
The Altair Clone accurately duplicates the timing of the original Altair
Floppy disk drive. While authentic, the slow speed can be frustrating after a
while! This menu allows choosing between maximum speed or real speed. Actual
speed is the default setting.
===== Floppy Performance =====
Current setting: Actual Speed
1) Actual Floppy Performance
) Maximum Floppy Performance
x) Exit this Menu
6. Baud Rate for Floppy Load/Save
When transferring floppy data from/to the PC (see “Floppy Disk Menu”), a
higher baud rate is used to speed up the transfer process. The default trans-
fer rate is 115. K baud. This menu allows selection of a different rate.
===== Set Floppy Load/Save Baud Rate =====
Current baud rate is 115. K
1) 9600
) 19. K
3) 38.4K
4) 57.6K
5) 76.8K
6) 115. K (recommended)
7. Single Step “Down” Options
Single step on the 8800 is performed by raising the Single-Step switch.
Pressing down on the Single-Step switch does nothing. In the 8800b computer,
however, pressing and holding the Single-Step switch in the down position au-
to-stepped at a rate determined by jumpers on the front panel board. This
menu option allows the user to choose similar features for Clone’s Single-
Steps switch. The default setting is for this feature to be disabled.

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===== Single-Step "Down" Options =====
Current setting: Disabled
1) Disabled
) Single-Step
3) 1 Auto-Step per second
4) Auto-Steps per second
5) 4 Auto-Steps per second
6) 8 Auto-Steps per second
x) Exit this Menu
8. Restore Defaults
Use the “Restore Defaults” menu option to restore all options and content to
their original values.
===== Restore Defaults =====
This operation will erase all floppy and PROM content
and set all parameters to their defaults values.
Restore defaults (y/n)?
9. Update Firmware
The “Update Firmware” menu option is used to install a firmware update into
the Altair 8800 Clone. Only perform this step if you have been instructed to
perform the update. See also the “Cold-Start Update Procedure.”
===== Update Firmware =====
This operation updates the Altair 8800 Clone firmware.
Do not perform this operation unless you have been instructed
to perform the update.
Continue (y/n)?
Cold Start Firmware Update
If the Altair Clone is unresponsive, the firmware can be restored without us-
ing the Configuration Monitor. Terminal emulator settings for a cold start
update are the same as for the Configuration Monitor (9600 baud, 8N1). With
power off, raise and hold the left AUX switch in the up position, then turn
on power while continuing to hold AUX in the up position. After about two se-
conds, you will see the “Update Firmware” prompt shown above. The AUX switch
can then be released. Follow the prompts to complete the software update pro-
cess.

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PART 3 – TERMINAL EMULATOR
A. Overview
A terminal emulator running on a PC is a convenient way to duplicate the
functionality of a teletype, paper tape reader/punch, CRT terminal, cassette
interface, capture printer output, etc. To provide these capabilities and
other useful functions, a terminal emulator with the following capabilities
is recommended:
• 8-bit transmission of text files (e.g., paper tape reader).
• 8-bit reception of text files (e.g., paper tape punch).
• Per character and/or per line delays when transmitting a text file.
• Terminal emulation should include an 8-bit mode in which the 8th bit is
ignored (assumed by 4K and 8K BASIC). Note, if the emulator supports a
7-bit plus parity mode in which the received parity is ignored, this
will also work.
• Support for original XMODEM (checksum) file send and receive.
B. TeraTerm Terminal Emulator
On the Windows platform The TeraTerm emulator meets all of the requirements
listed above. TeraTerm is now an Open Source project maintained at:
http://ttssh .sourceforge.jp/index.html.en
The version of TeraTerm maintained at the link above is much newer than the
version found at the “TeraTerm Home Page.” The latter is not recommended.
C. Installing TeraTerm
Installation files for TeraTerm are available on the AltairClone.com website
under the Support link. The installation files are also included in the All
Manuals and Software as a .zip file link.
Follow these steps to install TeraTerm:
1) Extract all files from the downloaded .zip file.
) Install TeraTerm by running the file teraterm-4.77.exe
Note: On the "Select Components" installation page, you can de-select
all optional components.
3) Copy the files "keyboard.cnf", "baud115k.ttl" and "baud9600.ttl" to the
program folder in which TeraTerm was installed.
4) Copy the file "teraterm.ini" file to the "My Documents" folder.
D. Configuring TeraTerm
When TeraTerm is launched, it loads its configuration from the "teraterm.ini"
file it finds in the "My Documents" folder. Step 4 above put a sample con-
figuration file in the “My Documents” folder. The first time TeraTerm is
started, you will probably have to select a different COM port under "Setup-
>Serial Port." After choosing the proper COM port, save the configuration by
choosing "Setup->Save setup" and over-writing the "termaterm.ini" file in the
"My Documents" folder.

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E. Using TeraTerm
The most commonly used menu options are:
File->Send File Sends a file over the serial port with no protocol
(e.g., paper tape or cassette, or non-XMODEM “Send File” operations
in the Configuration Monitor). Be sure the "Binary" checkbox at the
bottom of the file dialog box is checked.
File->Log... Receives a file over the serial port with no protocol
(e.g., paper tape or cassette). Be sure the "Binary" checkbox at the
bottom of the file dialog box is checked. When the file log operation
is started, a new taskbar tile appears (TeraTerm:Log). When file re-
ception is complete, click on the log taskbar tile and then click the
“Close” button to complete the file receive operation.
File->Transfer->Xmodem Used to send and receive files using the XMODEM
protocol. The Configuration Monitor uses XMODEM transfers to exchange
floppy disk content with the Clone. Also, the CP/M utilities “PCGET”
and “PCPUT” use the XMODEM protocol to transfer files between the Al-
tair and a PC.
Setup->Serial Port... Used to change baud rate, bits, parity, delay per
character and line, etc.
The following keyboard macros are enabled if step 3 was done correctly during
installation:
CTRL-1 changes to 115, 00 baud (for transferring floppy content)
CTRL-9 changes to 9,600 baud (default baud rate)
Note: The current baud rate is visible in the title bar of the TeraTerm win-
dow.

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PART 4 – ALTAIR 8800 DEMONSTRATIONS
This section contains step-by-step instructions for several popular Altair
demonstrations. These demonstrations assume you have downloaded the support
package from the AltairClone.com website: Click on the Support link at the
top of any page, then click on the All Manuals and Software as a .zip file
link. Extract all files from the zip file to your computer.
These demonstrations just scratch the surface of what can be done and learned
with your Altair 8800 Clone. Be sure to dig through the documentation and
software provided in the downloaded support package – you will find a wealth
of useful manuals and software. Keep in mind that some of the software is
“hidden” on Altair floppy disk images that can be seen only after the floppy
is loaded on to the Altair. This includes files on Altair BASIC disks, the
Altair DOS disk and on CP/M disks.
A. Kill-the-Bit Front Panel Game
Kill the Bit was one of the first games for the Altair. It runs on the front
panel of the Altair and does not require connection to an external teletype
or terminal. Following is the assembly language listing of the program:
;
; Kill the Bit game by Dean McDaniel, May 15, 1975
;
; Object: Kill the rotating bit. If you miss the lit bit,
; another bit turns on leaving two bits to destroy. Quickly
; toggle the switch, don't leave the switch in the up
; position. Before starting, make sure all the switches
; are in the down position.
0000 org 0
0000 10000 lxi h,0 ;initialize counter
0003 1680 mvi d,080h ;set up initial display bit
0005 010E00 lxi b,0eh ;higher value = faster
0008 1A beg: ldax d ;display bit pattern on
0009 1A ldax d ;...upper 8 address lights
000A 1A ldax d
000B 1A ldax d
000C 09 dad b ;increment display counter
000D D 0800 jnc beg
0010 DBFF in 0ffh ;input data from sense switches
001 AA xra d ;exclusive or with A
0013 0F rrc ;rotate display right one bit
0014 57 mov d,a ;move data to display reg
0015 C30800 jmp beg ;repeat sequence
0018 end
To run the program, it must first be entered into the Altair’s memory using
the front panel switches. The front panel switches are grouped such that data
entry from an octal dump is easiest. Following is a dump of each byte of the
program in octal:

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Addr Data
---- ----
Addr Data
---- ----
Addr Data
---- ----
000 041
001 000
00 000
003 0 6
004 00
005 001
006 016
007 000
010 03
011 03
01 03
013 03
014 011
015 3
016 010
017 000
0 0 333
0 1 377
0 5
0 3 017
0 4 1 7
0 5 303
0 6 010
0 7 000
Follow these steps to enter the program:
1) Turn the power switch on.
) Raise and hold the STOP switch in the STOP position, then raise and re-
lease the RESET switch. Finally, release the STOP switch. This performs
a hard reset on the computer and sets all address lights to zero.
3) Put the first data byte in switches 7 through 0, then raise DEPOSIT.
4) Put the data for the next address in switches 7 through 0, then depress
DEPOSIT NEXT.
5) Repeat step 4 until all bytes have been entered.
6) Raise and release RESET to force all address lights back to zero.
7) Verify the data shown on lights D7 through D0 matches the data byte for
the current address. If the value is correct, go to step 9, otherwise
go to step 8.
8) Put the correct value in switches 7 through 0, then raise DEPOSIT.
9) Depress EXAMINE NEXT
10) Repeat steps 7 through 9 to validate entry of the entire program.
Once the program is entered, you’re ready to play Kill the Bit! Read the in-
structions in the program listing above, then follow the steps below to run
the game.
1) Set all address switches to zero.
) Raise EXAMINE (or raise RESET) to set all address lights (and the 8080
program counter) to zero.
3) Depress RUN to run the program.
To start the game over, raise and release RESET. To change the rate at which
the light moves, change the byte at address 6 from 016 to a different value.
Higher values move the light faster, lower values move the light slower.

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B. Loading and Using 4K BASIC from Paper Tape
In this demonstration, we will load 4K BASIC Version 3. from paper tape. In
the mid-1970’s, a teletype connected to single serial port on the Altair
would have served as both the console and paper tape reader. We will dupli-
cate this configuration using a terminal emulator on a PC as both the console
and paper tape reader.
Computer Configuration
For this exercise, serial port #1 on the Altair Clone (the upper DB- 5
connector) should be configured as a SIO port at octal I/O address 0/ 1.
This is a standard Altair configuration. This is also the default Altair
Clone configuration. You can confirm or change the Clone’s serial port
configuration if needed. See “Serial Port Menu” in Part , “Configuration
Monitor” of this manual.
The default baud rate for the serial port on the Clone is 9600 baud. While
this is much faster than the 110 baud at which a real teletype operates,
we recommend using 9600 baud for this demonstration. Buffering in the PC’s
serial port drivers and issues with some USB-to-Serial adapters can make
operation at 110 and 300 baud problematic.
Terminal Emulator Configuration
The TeraTerm terminal emulator is used to duplicate the functionality of a
teletype. Confirm serial settings of 9600 baud, 8 bits, no parity, one
stop bit (8N1) in the “Setup->Serial Port” menu in TeraTerm. Also confirm
that the “Transmit Delay” fields are both set to zero.
To load 4K BASIC, we must first enter a small program via the front panel
called a “bootstrap loader.” The job of the bootstrap loader is to receive a
second loader from paper tape called the “checksum loader.” The checksum
loader is at the beginning of the BASIC paper tape. Once the checksum loader
has been read into memory, the checksum loader then reads in BASIC from the
remainder of the paper tape.
The code for the bootstrap loader is provided by Altair in the BASIC manual.
Different versions of the bootstrap loader are required based on the version
of BASIC and the type of interface card being used. For this demonstration,
we need the bootstrap loader for the 88- SIO serial board and for 4K BASIC
Version 3. . Following is the bootstrap loader code for this combination of
BASIC and serial port type:
Addr Data
---- ----
Addr Data
---- ----
Addr Data
---- ----
Addr Data
---- ----
000 076
001 003
00 3 3
003 0 0
004 076
005 0 5
006 3 3
007 0 0
010 041
011 56
01 017
013 061
014 03
015 000
016 333
017 0 0
0 0 017
0 1 3 0
0 333
0 3 0 1
0 4 75
0 5 310
0 6 055
0 7 167
030 300
031 351
03 013
033 000
Follow these steps to enter the bootstrap loader:
1) Turn the power switch on.
) Raise and hold the STOP switch in the STOP position, then raise and re-
lease the RESET switch. Finally, release the STOP switch. This performs
a hard reset on the computer and sets all address lights to zero.
3) Put the first data byte in switches 7 through 0, then raise DEPOSIT.

- 18 -
4) Put the data for the next address in switches 7 through 0, then depress
DEPOSIT NEXT.
5) Repeat step 4 until all bytes have been entered.
6) Raise and release RESET to force all address lights back to zero.
7) Verify the data shown on lights D7 through D0 matches the data byte for
the current address. If the value is correct, go to step 9, otherwise
go to step 8.
8) Put the correct value in switches 7 through 0, then raise DEPOSIT.
9) Depress EXAMINE NEXT
10) Repeat steps 7 through 9 to validate entry of the entire program.
Once the bootstrap loader is entered and verified, we’re almost ready to load
the BASIC paper tape. But first, we must set the run address to zero and then
set the front panel sense switches to tell the checksum loader and BASIC the
type of serial port that is in use:
1) Set all address switches to zero.
) Raise EXAMINE to set all address lights (and the 8080 program counter)
to zero.
3) Raise A11 and A10 to the up position. This tells the checksum loader
and BASIC that you are using a SIO serial board with one stop bit to
load BASIC and to use as your console.
Now we’re finally ready to actually load BASIC!
1) Depress RUN to run the bootstrap loader. If the loader was entered cor-
rectly, address lights A1 , and A4-A0 should be on.
) Transmit the paper tape image by using the “File->Send File” menu op-
tion in TeraTerm. Browse to and select the file “4K Basic Ver 3- .tap”
which is located in the “Paper Tape and Cassette” folder inside the
“BASIC” folder. Be sure the “binary” checkbox at the bottom of the send
file dialog is checked when sending a paper tape file.
3) Loading BASIC will only take about five seconds at 9600 baud (instead
of seven minutes at 110 baud!). Once loaded, BASIC initializes and
prompts the user for memory size. The prompt may look a bit garbled as
shown:
MEMORY SIZã?
This occurs because 4K BASIC uses bit 7 to store additional informa-
tion. However, because teletypes ignored bit 7, this did not cause a
problem. We can duplicate this effect in TeraTerm by choosing “Setup-
>Serial Port” and setting the “Data” field to 7 bits, and setting the
“Parity” field to “Space.” (Note: These settings must be returned to
8N1 if you need to start over and send the paper tape file once again).
4) Turn on “Caps Lock” on the keyboard.
5) In response to the “MEMORY SIZE” prompt, key in 0000 and press return.
(You can simply press RETURN and let BASIC determine memory size as
long as you have a PROM installed. Otherwise, BASIC will loop forever
and clobber itself while it looks for the end of RAM!).
6) In response to the “TERMINAL WIDTH” prompt, press RETURN.
7) In response to the “WANT SIN?” prompt, key in “Y” and press return.